Systems and Methods for Beneficiation of Bauxite Residue

This application claims priority to U.S. Provisional Application No. 63/663,746, filed on Jun. 25, 2024, which is hereby incorporated by reference in its entirety.

The present disclosure relates to systems and methods for beneficiating and/or recovering one or more elements from bauxite residue. Some aspects of the present disclosure relate to systems and methods for the beneficiating and/or recovering vanadium, chromium, iron, aluminum, calcium, silicon, titanium, or a combination thereof, from bauxite residue.

Bauxite residue is a by-product formed during alumina production from bauxite ore. For example, bauxite residue may be formed when alumina is produced using the Bayer process. Bauxite residue can vary in composition, and may include iron, aluminum, titanium, calcium, silicon, and sodium. Depending on the location and composition of source bauxite, the resulting bauxite residue can vary in water content, pH, density, and viscosity. Bauxite residue may also be referred to as red mud, bauxite tailings, or alumina refining residues.

Most bauxite residue remains stored at the site of alumina production due to a lack of commercially viable systems and methods for repurposing the bauxite residue. Storage and handling of bauxite residue can result in significant costs. Accordingly, there exists a need for systems and methods for beneficiating bauxite residue. There also exists a need for systems and methods for recovering materials of value from bauxite residue.

The present disclosure includes systems for beneficiating bauxite residue. For example, the system may comprise a first reaction vessel configured to receive a first stream comprising vanadic acid (HVO) and a second stream comprising an alkaline solution; a third stream passed from the first reaction vessel, wherein the third stream comprises a metavanadate salt; a filter configured to separate a vanadium-rich stream from the third stream; a second reaction vessel configured to receive a fourth stream comprising scandium carbonate (Sc(CO)) and a fifth stream comprising an organic acid; a fifth stream passed from the second reaction vessel, wherein the fifth stream comprises at least approximately 0.1 wt. % of a salt comprising scandium, based on the total weight of the fifth stream. The first stream may be derived from bauxite residue, and the fourth stream may be derived from bauxite residue. The fifth stream may comprise at least approximately 1.0 wt. % of the salt comprising scandium.

In some aspects, the vanadium-rich stream may comprise at least approximately 95 wt. % of the metavanadate salt, based on the total weight of solids in the vanadium-rich stream. The metavanadate salt may include ammonium metavanadate (NHVO). The salt may comprise scandium includes scandium oxalate (Sc(CO)). The filter may be further configured to separate a sixth stream from the third stream, wherein the sixth stream comprises a chromate salt. The system may further comprise a third reaction vessel configured to receive the sixth stream and a seventh stream comprising a bisulfite salt; and an eighth stream comprising chromium oxide (CrO) passed from the third reaction vessel.

In some aspects, the filter may be a first filter, and the system may further comprise a second filter configured to separate a titanium/calcium/silicon-rich stream and the fourth stream from a sixth stream, wherein the sixth stream comprises scandium carbonate (Sc(CO)), calcium carbonate (CaCO), one or more calcium aluminosilicates, and titanium dioxide (TiO).

The system may comprise a first reaction vessel configured to receive a first stream and an alkaline solution, wherein the first stream is derived from bauxite residue. The system may include a first filter configured to separate a leach residue and a leach filtrate from a leachate passed from the first reaction vessel. The system may include a second reaction vessel configured to roast a mixture including the leach residue, wherein roasting the mixture including the leach residue generates a metallized residue. The system may include a third reaction vessel configured to receive a second stream and oxalic acid, wherein the second stream comprises at least a portion of the metallized residue. The third reaction vessel may be configured to receive a third stream passed from the third reaction vessel, wherein the third stream comprises: at least approximately 1.0 wt. % scandium oxalate (Sc(CO)), at least approximately 1.0 wt. % zirconyl oxalate (ZrOCO), or both, based on the total weight of the third stream. Roasting the mixture including the leach residue may also generate roasting off-gas, and the system may further comprise a fourth reaction vessel configured to receive the roasting off-gas and a fourth stream comprising at least a portion of the leach filtrate. The system may further comprise a second filter configured to separate an aluminum-rich stream and a precipitate filtrate from an aluminum slurry passed from the fourth reaction vessel, wherein the aluminum-rich stream comprises at least 95 wt. % of an aluminum salt, based on the total weight of solids in the aluminum slurry. The system may further comprise an evaporator configured to remove water from a fifth stream, which may include at least a portion of the precipitate filtrate.

In some aspects, the system may further comprise a fourth reaction vessel configured to receive a solution comprising calcium hydroxide and fourth stream comprising at least a portion of the leach filtrate. The system may include a second filter configured to separate a phosphorous-containing compound and a purified filtrate from a fifth stream passed from the fourth reaction vessel. The system may further comprise a fifth reaction vessel configured to receive a solution comprising a hydroxide salt and fifth stream comprising at least a portion of the purified filtrate. The system may further include a third filter configured to separate a vanadium-rich stream from a sixth stream passed from the fifth reaction vessel. The vanadium-rich stream may include at least 95 wt. % of a compound comprising vanadium, based on the total weight of the vanadium-rich stream.

The present disclosure also includes methods for beneficiating bauxite residue. For example, the method may comprise: introducing bauxite residue and sodium carbonate (NaCO) to a dryer; blending and drying the sodium carbonate (NaCO) and bauxite residue in the dryer, thereby forming dried bauxite residue; introducing an alkaline solution and a stream including the dried bauxite residue to a first reaction vessel, and forming a leachate within the first reaction vessel; separating a leach residue and a leach filtrate from the leachate; precipitating a phosphorous-containing compound, a vanadium-containing compound, or both, out of the leach filtrate, thereby forming a purified leachate; and precipitating a salt, out of the purified leachate, wherein the salt comprises aluminum. The phosphorous-containing compound may be a hydroxyphosphate salt, and the vanadium-containing compound may be a metavanadate salt. The method may further comprise roasting the leach residue, to form a roasted leach residue and roasting off-gas; magnetically separating iron-containing species from the roasted leach residue, thereby forming a slag residue; introducing the slag residue the roasting-off gas to a second reaction vessel, and forming a precipitate in the second reaction vessel. In some aspects, the stream including the dried bauxite residue may be a first stream. In these aspects, the method may further comprise: introducing oxalic acid and a second stream to a second reaction vessel, wherein the second stream is derived from the leach residue; and passing a third stream from the second reaction vessel, wherein the third stream comprises scandium oxalate (Sc(CO)) and zirconyl oxalate (ZrOCO).

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any suitable methods and materials (e.g., similar or equivalent to those described herein) can be used in the practice or testing of the present disclosure, particular example methods are now described. All publications mentioned are hereby incorporated by reference.

As used herein, the terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. The term “exemplary” is used in the sense of “example,” rather than “ideal.” For the terms “for example” and “such as,” and grammatical equivalences thereof, the phrase “and without limitation” is understood to follow unless explicitly stated otherwise.

As used herein, the term “approximately” is meant to account for variations due to experimental error. When applied to numeric values, the term “approximately” may indicate a variation of +/−5% from the disclosed numeric value, unless a different variation is specified. As used herein, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Further, all ranges are understood to be inclusive of endpoints, e.g., from 1 meter to 5 meters would include lengths of 1 meter, 5 meters, and all lengths between 1 meter and 5 meters.

It should be noted that all numeric values disclosed or claimed herein (including all disclosed values, limits, and ranges) may have a variation of +/−5% from the disclosed numeric value unless a different variation is specified.

In describing embodiments of the present disclosure, part names are intended to be descriptive and not limiting. For example, methods and systems described herein may include streams comprising a combination of substances. For clarity, a stream may be named according to one or more components of the stream. In addition or alternatively, streams may be named according to their relative position within a process or system. The name of a particular stream or component of a method or system described herein should not be considered limiting on the composition or properties of the named stream or component. For example, “ammonium metavanadate stream” may comprise ammonium metavanadate, and/or any number of other species, as described herein. As another example “purified aluminum leachate,” has a composition as described herein, and is not necessarily limited to compositions having undergone a purification process, combinations including aluminum, or leachates from a leaching operation.

Bauxite residue may comprise aluminum, arsenic, calcium, cerium, chromium, iron, lanthanum, lead, magnesium, manganese, nickel, neodymium, niobium, scandium, silicon, strontium, thorium, titanium, vanadium, yttrium, and/or zirconium. For example, bauxite residue may comprise aluminum hydroxide oxide (AlO(OH)), anatase (TiO), arsenic trioxide (AsO), boehmite (α-AlO·HO), calcite (CaCO), calcium carbonate (CaCO), calcium hydroxide (Ca(OH)), calcium hydroxyphosphate (Ca(OH)(PO)), calcium sulfate dihydrate (CaSO·2HO), cancrinite (NaCa[(CO)|AlSiO]·2HO), cerium oxide (CeO), chromium oxide (CrO), diaspore (β-AlO·HO), ferric oxide (FeO), ferric oxyhydroxide (FeO(OH)), ferryhydrite (FeO·0.5HO), gibbsite (α-AlO·3HO), goethite (FeO(OH)), halloysite (AlSiO(OH)), hematite (α-FeO), hydroxyapatite (Ca(PO)OH), hydroxylapatite (Ca(PO)OH), ilmenite (FeO·TiO), kaolinite (AlSiO(OH)), lanthanum (III) oxide (LaO), lead (II) oxide (PbO), maghemite (γ-FeO), magnesium hydroxide (Mg(OH)), magnetite (FeO), manganese (II) hydroxide (Mn(OH)), monazite ((Ce,La,Pr,Nd,Th,Y)PO), neodymium (III) oxide (NdO), nickel (II) oxide (NiO), niobium pentoxide (NbO), perovskite (CaTiO), portlandite (Ca(OH)), potassium oxide (KO), pyrite (FeS), quartz (SiO), rutile (TiO), scandium oxide (ScO), silicon dioxide (SiO), sillimanite (AlSiO), sodalite (Na(AlSiO)Cl), sodium aluminate (NaAlO), sodium metasilicate (NaSiO), strontium oxide (SrO), synchysite-(Ce) (CaCe(CO)F), thorium dioxide (ThO), titanium dioxide (TiO), vanadium pentoxide (VO), xenotime (YPO), yttrium (III) oxide (YO), zirconium dioxide (ZrO), or a combination thereof.

Bauxite residue may comprise solid and/or aqueous phases. In some embodiments, bauxite residue may comprise approximately 15-45 weight percent (wt. %) water, based on the total weight of the bauxite residue. Bauxite residue comprising 15-30 wt. % water may be stored in a dry storage location, and bauxite residue comprising 30-45 wt. % water may be stored in retention ponds. The systems and methods of the present disclosure may be used with bauxite residue comprising any water content, such as, for example, bauxite residue from dry storage and/or bauxite residue from a retention pond. As described herein, the steps of a process for beneficiating bauxite residue may be modified, adjusted, and/or reordered depending on the composition of the bauxite residue being beneficiated.

In some embodiments, a process for beneficiating bauxite residue includes improving the recoverability of one or more elements in bauxite residue. A system for beneficiating bauxite residue may be configured to facilitate a process for beneficiating bauxite residue and/or improve the recoverability of one or more elements in bauxite residue.

In some embodiments, a process for beneficiating bauxite residue includes improving the recoverability of vanadium, and/or recovering vanadium. For example, a process for beneficiating bauxite residue may generate one or more compounds including vanadium that are suitable for storage, transport, and/or use. By way of non-limiting example, vanadium compounds generated by methods and systems of the present disclosure may include ammonium metavanadate ((NH)VO).

In some embodiments, a process for beneficiating bauxite residue includes improving the recoverability of chromium, and/or recovering chromium. For example, a process for beneficiating bauxite residue may generate one or more compounds including chromium that are suitable for storage, transport, and/or use. By way of non-limiting example, chromium compounds generated by methods and systems of the present disclosure may include chromium oxide (CrO).

In some embodiments, a process for beneficiating bauxite residue includes improving the recoverability of aluminum, and/or recovering aluminum. For example, a process for beneficiating bauxite residue may generate one or more compounds including aluminum that are suitable for storage, transport, and/or use. By way of non-limiting example, aluminum compounds generated by methods and systems of the present disclosure may include aluminum hydroxide (Al(OH)).

In some embodiments, a process for beneficiating bauxite residue includes improving the recoverability of iron, and/or recovering iron. For example, a process for beneficiating bauxite residue may generate one or more compounds including iron that are suitable for storage, transport, and/or use. By way of non-limiting example, iron compounds generated by methods and systems of the present disclosure may include elemental iron, such as, for example, pig iron.

In some embodiments, a process for beneficiating bauxite residue includes improving the recoverability of calcium, and/or recovering calcium. For example, a process for beneficiating bauxite residue may generate one or more compounds including calcium that are suitable for storage, transport, and/or use. By way of non-limiting example, calcium compounds generated by methods and systems of the present disclosure may include calcium carbonate (CaCO).

In some embodiments, a process for beneficiating bauxite residue includes improving the recoverability of silicon, and/or recovering silicon. For example, a process for beneficiating bauxite residue may generate one or more compounds including silicon that are suitable for storage, transport, and/or use. By way of non-limiting example, silicon compounds generated by methods and systems of the present disclosure may include calcium aluminosilicate (CaAlSiO).

In some embodiments, a process for beneficiating bauxite residue includes improving the recoverability of titanium, and/or recovering titanium. For example, a process for beneficiating bauxite residue may generate one or more compounds including titanium that are suitable for storage, transport, and/or use. By way of non-limiting example, titanium compounds generated by methods and systems of the present disclosure may include titanium dioxide (TiO).

In some embodiments, a process for beneficiating bauxite residue includes improving the recoverability of scandium, and/or recovering scandium. For example, a process for beneficiating bauxite residue may generate one or more compounds including scandium that are suitable for storage, transport, and/or use. By way of non-limiting example, scandium compounds generated by methods and systems of the present disclosure may include scandium oxalate (Sc(CO)).

In some embodiments, a process for beneficiating bauxite residue includes improving the recoverability of zirconium, and/or recovering zirconium. For example, a process for beneficiating bauxite residue may generate one or more compounds including zirconium that are suitable for storage, transport, and/or use. By way of non-limiting example, zirconium compounds generated by methods and systems of the present disclosure may include zirconyl oxalate (ZrOCO).

Referring to, a processfor beneficiating bauxite residuemay include the generation of a vanadium-rich stream, an aluminum-rich stream, an iron-rich stream, a calcium/silicon/titanium-rich stream, and/or a scandium-rich stream. The vanadium-rich streammay include one or more vanadium species that have improved availability, compared to the vanadium species present in bauxite residue. For example, vanadium-rich streammay comprise ammonium metavanadate ((NH)VO). Vanadium-rich streammay comprise greater than or equal to approximately 95 wt. % vanadium compounds, based on the total weight of solids in vanadium-rich stream, such as, for example, approximately 95 wt. % to approximately 100 wt. %, greater than or equal to approximately 99 wt. %, approximately 99 wt. % to approximately 100 wt. %, greater than or equal to approximately 99.9 wt. %, or approximately 100 wt. % vanadium compounds (e.g., ammonium metavanadate ((NH)VO)). In some embodiments, vanadium-rich streammay include solid and aqueous phases. The aqueous phase of vanadium-rich streammay include vanadic acid (HVO), sodium hydroxide (NaOH), sodium chromate (NaCrO), or a combination thereof.

The aluminum-rich streammay include one or more aluminum species that have improved availability, compared to the aluminum species present in bauxite residue. For example, aluminum-rich streammay comprise aluminum hydroxide (Al(OH)). Aluminum-rich streammay comprise greater than or equal to approximately 95 wt. % aluminum compounds, based on the total weight of solids in aluminum-rich stream, such as, for example, approximately 95 wt. % to approximately 100 wt. %, greater than or equal to approximately 99 wt. %, approximately 99 wt. % to approximately 100 wt. %, greater than or equal to approximately 99.9 wt. %, or approximately 100 wt. % aluminum compounds (e.g., aluminum hydroxide (Al(OH))). In some embodiments, aluminum-rich streammay include solid and aqueous phases. The aqueous phase of aluminum-rich streammay include oxalic acid (CHO), vanadic acid (HVO), sodium carbonate (NaCO), sodium dihydrogen arsenite (NaHAsO), disodium phosphate (NaHPO), sodium bicarbonate (NaHCO), sodium hydrogen metasillicate (NaHSiO), sodium chromate (NaCrO), ammonium hydroxide (NHOH), scandium oxalate (Sc(CO)), zirconyl oxalate (ZrOCO), or a combination thereof. In addition to one or more aluminum compounds (e.g., Al(OH)), aluminum-rich streammay include vanadium pentoxide (VO).

The iron-rich streammay include one or more iron species that have improved availability, compared to the iron species present in bauxite residue. For example, iron-rich streammay comprise iron (Fe). Iron-rich streammay comprise greater than or equal to approximately 90 wt. % iron, based on the total weight of iron-rich stream, such as, for example, approximately 90 wt. % to approximately 100 wt. %, greater than or equal to approximately 92 wt. %, greater than or equal to approximately 95 wt. %, greater than or equal to approximately 97 wt. %, greater than or equal to approximately 99 wt. %, approximately 92 wt. % to approximately 100 wt. %, or approximately 95 wt. % to approximately 100 wt. %. In some embodiments, iron-rich streammay include carbon (C), calcium aluminosilicate (CaAlSiO), calcium orthosilicate (CaSiO), calcium hydroxyphosphate (Ca(OH)(PO)), calcium sulfate dihydrate (CaSO·2HO), calcium oxide (CaO), iron phosphide (FeP), potassium oxide (KO), lanthanum oxide (LaO), manganese oxide (MnO), sodium carbonate (NaCO), neodymium oxide (NdO), arsenic trioxide (AsO), calcium hydroxide (Ca(OH)), cerium oxide (CeO), magnesium oxide (MgO), niobium pentoxide (NbO), nickel (II) oxide (NiO), lead (II) oxide (PbO), scandium oxide (ScO), strontium oxide (SrO), thorium dioxide (ThO), titanium dioxide (TiO), vanadium pentoxide (VO), yttrium (III) oxide (YO), zirconium dioxide (ZrO), or a combination thereof.

The calcium/silicon/titanium-rich streammay include one or more species of calcium that have improved availability, compared to the calcium species present in bauxite residue. In addition or alternatively, calcium/silicon/titanium-rich streammay include one or more species of silicon that have improved availability, compared to the silicon species present in bauxite residue. In addition or alternatively, calcium/silicon/titanium-rich streammay include one or more species of titanium that have improved availability, compared to titanium species present in bauxite residue. For example, calcium/silicon/titanium-rich streammay comprise calcium aluminosilicate (CaAlSiO), calcium carbonate (CaCO), titanium dioxide (TiO), or a combination thereof.

Calcium/silicon/titanium-rich streammay comprise greater than or equal to approximately 5 wt. % calcium aluminosilicate (CaAlSiO), based on the total weight of solids within calcium/silicon/titanium-rich stream, such as, for example, approximately 5 wt. % to approximately 25 wt. %, approximately 10 wt. % to approximately 25 wt. %, approximately 15 wt. % to approximately 25 wt. %, approximately 10 wt. % to approximately 20 wt. %, approximately 15 wt. % to approximately 20 wt. %, approximately 16 wt. %, greater than or equal to approximately 10 wt. %, or greater than or equal to approximately 15 wt. %.

Calcium/silicon/titanium-rich streammay comprise greater than or equal to approximately 15 wt. % calcium carbonate (CaCO), based on the total weight of solids within calcium/silicon/titanium-rich stream, such as, for example, greater than or equal to approximately 20 wt. %, greater than or equal to approximately 25 wt. %, greater than or equal to approximately 30 wt. %, greater than or equal to approximately 35 wt. %, approximately 15 wt. % to approximately 50 wt. %, approximately 20 wt. % to approximately 50 wt. %, approximately 25 wt. % to approximately 50 wt. %, approximately 30 wt. % to approximately 50 wt. %, approximately 5 wt. % to approximately 40 wt. %, approximately 10 wt. % to approximately 35 wt. %, approximately 25 wt. % to approximately 45 wt. %, approximately 30 wt. % to approximately 40 wt. %, or approximately 35 wt. %.

Calcium/silicon/titanium-rich streammay comprise greater than or equal to approximately 5 wt. % titanium dioxide (TiO), based on the total weight of solids within calcium/silicon/titanium-rich stream, such as, for example, approximately 5 wt. % to approximately 25 wt. %, approximately 10 wt. % to approximately 25 wt. %, approximately 15 wt. % to approximately 25 wt. %, approximately 10 wt. % to approximately 20 wt. %, approximately 15 wt. % to approximately 20 wt. %, approximately 19 wt. %, greater than or equal to approximately 10 wt. %, or greater than or equal to approximately 15 wt. %.

In some embodiments, calcium/silicon/titanium-rich streammay include a solid phase and an aqueous phase. The solid phase of calcium/silicon/titanium-rich streammay comprise arsenic trioxide (AsO), calcium aluminosilicate (CaAlSiO), calcium hydroxide (Ca(OH)), calcium hydroxyphosphate (Ca(OH)(PO)), calcium orthosilicate (CaSiO), calcium sulfate dihydrate (CaSO·2HO), calcium magnesium carbonate (CaMg(CO)), calcium carbonate (CaCO), manganese carbonate (MnCO), carbon (C), cerium oxide (CeO), iron (Fe), iron phosphide (FeP), lanthanum (III) oxide (LaO), lead (II) oxide (PbO), manganese oxide (MnO), neodymium (III) oxide (NdO), nickel (II) oxide (NiO), niobium pentoxide (NbO), potassium oxide (KO), scandium oxide (ScO), sodium carbonate (NaCO), sodium hydroxide (NaOH), strontium oxide (SrO), thorium dioxide (ThO), titanium dioxide (TiO), vanadium pentoxide (VO), yttrium (III) oxide (YO), zirconium dioxide (ZrO), or a combination thereof. The aqueous phase of calcium/silicon/titanium-rich streammay comprise oxalic acid (CHO), sodium chromate (NaCrO), sodium carbonate (NaCO), sodium bicarbonate (NaHCO), scandium carbonate (Sc(CO)), scandium oxalate (Sc(CO)), zirconyl oxalate (ZrO(CO)), ammonium hydroxide (NHOH), zirconyl hydroxide (ZrO(OH)), or a combination thereof.

The scandium-rich streammay include one or more species of scandium that have improved availability, compared to the scandium species present in bauxite residue. For example, scandium-rich streammay comprise scandium oxalate (Sc(CO)). In some embodiments, scandium-rich streamis an aqueous solution that also comprises zirconyl oxalate (ZrOCO). Scandium-rich streammay comprise greater than or equal to approximately 0.5 wt. % scandium oxalate (Sc(CO)), based on the total weight of scandium-rich stream, such as, for example, greater than or equal to approximately 0.5 wt. %, greater than or equal to approximately 1.0 wt. %, greater than or equal to approximately 1.2 wt. %, greater than or equal to approximately 1.5 wt. %, or approximately 0.5 wt. % to approximately 2.5 wt. %. Scandium-rich streammay comprise greater than or equal to approximately 0.5 wt. % zirconyl oxalate (ZrOCO), based on the total weight of scandium-rich stream, such as, for example, greater than or equal to approximately 1.0 wt. %, greater than or equal to approximately 1.5 wt. %, greater than or equal to approximately 1.8 wt. %, greater than or equal to approximately 2.0 wt. %, or approximately 0.5 wt. % to approximately 4.0 wt. %.

Still referring to, processmay include bauxite residue processing. Bauxite residue processingmay include mechanically and/or chemically breaking down the bauxite residueto increase the availability of constituent elements. For example, bauxite residue processingmay include drying the bauxite residue, blending the bauxite residuewith sodium carbonate, pelleting the blended bauxite residue, roasting the pelletized bauxite residue, grinding the roasted pellets, and/or leaching the roasted, pelletized, ground bauxite residue. Bauxite residue processingmay generate an aluminum leaching filtrateand an aluminum leaching residue.

In some embodiments, processincludes vanadium and phosphate separation. For example, the aluminum leaching filtratefrom bauxite residue processingmay be precipitated, ion-exchanged, and/or filtered to generate the vanadium-rich stream. An aluminum slurrymay also be generated during vanadium and phosphate separation. In some embodiments, processincludes aluminum separation. For example, the aluminum slurrymay be filtered to generate an aluminum-rich stream.

In some embodiments, processincludes iron separation. For example, aluminum leaching residuemay be further processed (e.g., briquetted, roasted, and/or ground). Iron from the processed aluminum leaching residuemay be magnetically separated to generate iron-rich stream. The remaining processed residuemay form a slag residue.

In some embodiments, processincludes calcium/silicon/titanium separation. For example, components of slag residuemay be carbonized and/or filtered. The residue from filtered carbonized slag residuemay be extracted and/or further processed to generate a calcium/silicon/titanium-rich stream.

The filtrate from carbonized slag residue(e.g., scandium carbonization filtrate) may be further processed to recover scandium. For example, processmay include scandium separation. Scandium separationmay include ion-exchanging the scandium carbonization filtrateto generate a scandium-rich stream.

Referring to, a processfor beneficiating bauxite residuemay include the generation of a vanadium-rich stream, an aluminum-rich stream, an iron-rich stream, a calcium/silicon/titanium-rich stream, and/or a scandium-rich stream.

Processmay comprise bauxite residue drying. In some embodiments, bauxite residue dryingmay include mixing and/or blending bauxite residuewith sodium carbonate (NaCO) (e.g., regenerated sodium carbonate). For example, sodium carbonate (NaCO) may be added in an amount equivalent to approximately 15% to approximately 35% of the weight of bauxite residue. In some embodiments, sodium carbonate (NaCO) may be added in an amount equivalent to approximately 25% of the weight of bauxite residue. The blended bauxite residueand sodium carbonate mixture may be dried. In some embodiments, the bauxite residue and sodium carbonate may be blended while being dried (e.g., utilizing a paddle dryer). During bauxite residue drying, liquid water may be converted to gaseous water (e.g., water vapor and/or steam).

A dried bauxite residuemay be generated during bauxite residue drying. Bauxite residue drying off-gasmay also be generated during bauxite residue drying. Dried bauxite residuemay include a solid phase, an aqueous phase, or both. The water content of dried bauxite residuemay be approximately one-third of the water content of bauxite residue. For example, the water content of dried bauxite residuemay be approximately 25% to approximately 75% of the water content of bauxite residue.

The solid phase of dried bauxite residuemay comprise aluminum hydroxide oxide (AlO(OH)), arsenic trioxide (AsO), calcium carbonate (CaCO), calcium hydroxide (Ca(OH)), calcium hydroxyphosphate (Ca(OH)(PO)), calcium sulfate dihydrate (CaSO·2HO), cerium oxide (CeO), chromium oxide (CrO), ferric oxide (FeO), ferric oxyhydroxide (FeO(OH)), lanthanum (III) oxide (LaO), lead (II) oxide (PbO), magnesium hydroxide (Mg(OH)), manganese (II) hydroxide (Mn(OH)), neodymium (III) oxide (NdO), nickel (II) oxide (NiO), niobium pentoxide (NbO), potassium oxide (KO), scandium oxide (ScO), silicon dioxide (SiO), sodium aluminate (NaAlO), sodium carbonate (NaCO), sodium metasilicate (NaSiO), sodium oxide (NaO), strontium oxide (SrO), thorium dioxide (ThO), titanium dioxide (TiO), vanadium pentoxide (VO), yttrium (III) oxide (YO), zirconium dioxide (ZrO), or a combination thereof. The aqueous phase of dried bauxite residuemay comprise water (HO), oxalic acid (CHO), disodium phosphate (NaHPO), sodium bicarbonate (NaHCO), sodium hydroxide (NaOH), sodium chromate (NaCrO), ammonium hydroxide (NHOH), scandium oxalate (Sc(CO)), zirconyl hydroxide (ZrO(OH)), or a combination thereof.

Bauxite residue drying off-gasmay include a solid phase, a gaseous phase, or both. The solid phase of bauxite residue drying off-gasmay comprise aluminum hydroxide oxide (AlO(OH)), arsenic trioxide (AsO), calcium carbonate (CaCO), calcium hydroxide (Ca(OH)), calcium hydroxyphosphate (Ca(OH)(PO)), calcium sulfate dihydrate (CaSO·2HO), cerium oxide (CeO), chromium oxide (CrO), ferric oxide (FeO), ferric oxyhydroxide (FeO(OH)), hydroxylapatite (Ca(PO)OH), lanthanum (III) oxide (LaO), lead (II) oxide (PbO), magnesium hydroxide (Mg(OH)), manganese (II) hydroxide (Mn(OH)), neodymium (III) oxide (NdO), nickel (II) oxide (NiO), niobium pentoxide (NbO), potassium oxide (KO), scandium oxide (ScO), silicon dioxide (SiO), sodium aluminate (NaAlO), sodium carbonate (NaCO), sodium metasilicate (NaSiO), sodium oxide (NaO), strontium oxide (SrO), thorium dioxide (ThO), titanium dioxide (TiO), vanadium pentoxide (VO), yttrium (III) oxide (YO), zirconium dioxide (ZrO), or a combination thereof. The gaseous phase of bauxite residue drying off-gasmay comprise water (HO), argon (Ar), carbon dioxide (CO), nitrogen (N), oxygen (O), or a combination thereof.

Processmay comprise blending and pelletizing. Blending and pelletizingmay include blending the dried bauxite residuewith one or more effluents or discharges from an off-gas recapture system. The blend may be pelletized to form bauxite residue pellets.

Bauxite residue pelletsmay include a solid phase, an aqueous phase, or both. The solid phase of bauxite residue pelletsmay comprise aluminum hydroxide oxide (AlO(OH)), arsenic trioxide (AsO), calcium carbonate (CaCO), calcium hydroxide (Ca(OH)), calcium hydroxyphosphate (Ca(OH)(PO)), calcium sulfate dihydrate (CaSO·2HO), cerium oxide (CeO), chromium oxide (CrO), ferric oxide (FeO), ferric oxyhydroxide (FeO(OH)), hydroxylapatite (Ca(PO)OH), lanthanum (III) oxide (LaO), lead (II) oxide (PbO), magnesium hydroxide (Mg(OH)), manganese (II) hydroxide (Mn(OH)), neodymium (III) oxide (NdO), nickel (II) oxide (NiO), niobium pentoxide (NbO), potassium oxide (KO), scandium oxide (ScO), silicon dioxide (SiO), sodium aluminate (NaAlO), sodium carbonate (NaCO), sodium metasilicate (NaSiO), sodium oxide (NaO), strontium oxide (SrO), thorium dioxide (ThO), titanium dioxide (TiO), vanadium pentoxide (VO), yttrium (III) oxide (YO), zirconium dioxide (ZrO), or a combination thereof. The aqueous phase of bauxite residue pelletsmay include water (HO), oxalic acid (CHO), disodium phosphate (NaHPO), sodium bicarbonate (NaHCO), sodium hydroxide (NaOH), sodium chromate (NaCrO), ammonium hydroxide (NHOH), scandium oxalate (Sc(CO)), zirconyl hydroxide (ZrO(OH)), or a combination thereof.

In some embodiments, processmay comprise a first off-gas scrubbing. The bauxite residue drying off-gasmay be scrubbed to generate a first off-gas scrubber effluent. For example, bauxite residue drying off-gasmay be passed through a scrubber (e.g., a venturi scrubber) while a liquid phase is introduced into the scrubber. The liquid phase may capture solids from residue drying off-gasto generate the first off-gas scrubber effluent.

The first off-gas scrubber effluentmay include a solid phase, an aqueous phase, or both. The first off-gas scrubber effluentmay comprise aluminum hydroxide oxide (AlO(OH)), arsenic trioxide (AsO), calcium carbonate (CaCO), calcium hydroxide (Ca(OH)), calcium hydroxyphosphate (Ca(OH)(PO)), calcium sulfate dihydrate (CaSO·2HO), cerium oxide (CeO), chromium oxide (CrO), ferric oxide (FeO), ferric oxyhydroxide (FeO(OH)), hydroxylapatite (Ca(PO)OH), lanthanum (III) oxide (LaO), lead (II) oxide (PbO), magnesium hydroxide (Mg(OH)), manganese (II) hydroxide (Mn(OH)), neodymium (III) oxide (NdO), nickel (II) oxide (NiO), niobium pentoxide (NbO), potassium oxide (KO), scandium oxide (ScO), silicon dioxide (SiO), sodium aluminate (NaAlO), sodium carbonate (NaCO), sodium metasilicate (NaSiO), sodium oxide (NaO), strontium oxide (SrO), thorium dioxide (ThO), titanium dioxide (TiO), vanadium pentoxide (VO), yttrium (III) oxide (YO), zirconium dioxide (ZrO), water (HO), or a combination thereof. First off-gas scrubber effluentmay be incorporated into bauxite residue pelletsduring blending and pelletizing.